Commit Message

From: Julian Anastasov <ja@ssi.bg>
BugLink: https://bugs.launchpad.net/bugs/883441
commit 64b3db22c04586997ab4be46dd5a5b99f8a2d390 (2.6.39),
"Remove use of unreliable FADT revision field" causes regression
for old P4 systems because now cst_control and other fields are
not reset to 0.
The effect is that acpi_processor_power_init will notice
cst_control != 0 and a write to CST_CNT register is performed
that should not happen. As result, the system oopses after the
"No _CST, giving up" message, sometimes in acpi_ns_internalize_name,
sometimes in acpi_ns_get_type, usually at random places. May be
during migration to CPU 1 in acpi_processor_get_throttling.
Every one of these settings help to avoid this problem:
- acpi=off
- processor.nocst=1
- maxcpus=1
The fix is to update acpi_gbl_FADT.header.length after
the original value is used to check for old revisions.
https://bugzilla.kernel.org/show_bug.cgi?id=42700
https://bugzilla.redhat.com/show_bug.cgi?id=727865
Signed-off-by: Julian Anastasov <ja@ssi.bg>Acked-by: Bob Moore <robert.moore@intel.com>Signed-off-by: Len Brown <len.brown@intel.com>
(upstream commit 3e80acd1af40fcd91a200b0416a7616b20c5d647)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/acpi/acpica/tbfadt.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)